Composition paving-block



(No Model.)

J. H. DRAKE.

COMPOSITION PAVING BLOOK.

NO. 451,466. Patented May 5,1891.

ZOOM I m2 Nome versus co., mare-Luna, WASHXNGTON, o. c.

UNITED STATES PATENT 'OFFICE.

JAMES I'IAINES DRAKE, OF ST. PAUL, MINNESOTA.-

COMPOSITION PAVING-BLOCK.

SPECIFICATION forming part of Letters Patent No. 451,466, dated May 5, 1891 Application filed December 3, 1890. Serial No. 373,459. (liospeciniens) To all whom it may concern:

Be it known that 1, JAMES HAINEs DRAKE, a citizen of the United States, residing at St. Paul, in the State of Minnesota, have invented certain new and useful Improvements in Composition Paving-Blocks and in Methods of Producing the Same, of which I do declare the following to be a full, clear, and exact descript-ion, reference being had to the accompanying drawings, forming part of this speci fication.

In the manufacture of paving-blocks of composition material it is of great importance that the upper surfaces of the blocks shall be of intense hardness, with the material so closely and firmly bound together and of such I homogeneous character that the surface shall resist the wear incident to the traffic on the roadway, and while presenting a smoothness shall not become so slippery or polished by wear as to afford an insecure footing for horses. A further desideratum is that the paving-blocks shall have their upper edges closely jointed, since otherwise the wear would be at the joints and the desired smoothness of the surface would be speedily destroyed. Again, it is highly important, particularly in the construction of pavements for streets on which heavy traffic prevails, that the pavingblooksshall be so firmly bedded and bound in place as to prevent any movement whatever when heavily-ladened wagons pass over them or from the impact of the horses feet. By my present invention I have produced a paving-block whereby the several desired ends above mentioned are effectually attained.

My invention consists in the novel features hereinafterdescribed, and particularly pointed out in the claims at the end of this specification.

Figure 1 is a top perspective view of a paving-block embodying my invention. Fig. 2 is a bottom perspective view thereof. Fig. 3 is a view in vertical section throughtwo adjoining paving-blocks in position upon the foundation.

In the practice of my invention I prefer to employ for the body B of the blocks a composition consisting of hydraulic cement, clean, coarse, and sharp sand, and quartzite rock. The proportions of these materials may be varied; but I have obtained the best results by using one portion of hydraulic cement to three portions of clean, coarse, sharp sand and three portions of crushed quartzite rock, the crushed rock varying in size from pieces which at their largest part will barely pass through a ring one-half inch in diameter up to pieces of rock which at their largest part will barely pass through a ring two and onehalf inches in diameter.

In Letters Patent No. 273,824, granted to David G. WVeems and myself March 13, 1883, is described a composite stone of which quartzite rock is the characteristic ingredient, and in such patent the advantages incident to the use of this peculiar stone are fullyset forth, and such'advantages have been fully demonstrated by long practice. The ingredients, preferably in the proportions above indicated, are moistened with water or other suitable liquid and thoroughly triturated and molded in form, great care being taken to tamp about the edges of the forms. Before the composition thus prepared is set within the mold or form I place upon the bottom of the mold a layer of about one-half to one inch of sand, and then set by hand in this sand pieces of broken quartzite D, with their larger ends upward. The pieces of quartzite are preferably embedded in the sand to a depth of about onehalf inch; but the upper ends and larger ends of these quartzite pieces will project to a distance above the top of the sand, so as to be thoroughly embedded in and form part of the body of the block. The ingredients in substantially the proportions above indicated are then rammed into the forms or molds. The interstices in the tops of the blocks are then filled with a mixture A, composed,preferably, of about equal parts of hydraulic cement and finely crushed quartzite, the particles of quartzite varying from the'size of a pea to that of grains of sand, and this mixture will be thoroughly troweled into the interstices immediately after the composition has been tamped in the forms and before it has set. To this mixture a solution of soda silicate maybe added, if desired, to hasten induration. The result of thus applyingthe mixture .of finely-broken quartzite and cement to the surface of the blocks is to give to such sur face a smooth and at the same time a sharp finish. The hard fine particles of the quartzite resist wear more effectively than does the bond of hydraulic cement, and as a consequence, while the upper surface of the blocks when in use remain smooth, still the result of the inequalityof wear in the quartzite and cement gives to the surface of the blocks a grain which prevents the blocks from being slippery and insures a secure footing for the horses. The blocks will be indurated by any of the usual processes known to the art. hen the blocks are withdrawn from the molds, it will be found that the broken pieces of quartzite will extendto adistance beyond the bottom su 1'- face of the blocks corresponding to the depth to which such pieces projected into the sand within the bottom of the mold, and the bottom of the block therefore is furnished with a sharp jagged surface, or rather a series of sharp jagged projections of irregular outline. These blocks will be placed upon a concrete or similar base or foundation, and before the cement of this base or foundation has set the blocks will be firmly seated, so as to drive the protruding pieces of quartzite into the foundation, and thus create a bond at the bottom of each block that firmly unites such block to the concrete base or foundation upon which it rests. By preference the molds in which the composition is formed have their sides inclined, as shown, in order to form the edges of the blocks beveled or inclined, as at C, so that the close joining of the blocks can be secured when crowning a roadway therewith. Moreover, this inward bevel gives space for an application of hydraulic cement or other binding-cement in the apertures produced by the beveled edges of the blocks, thus enabling the blocks to be more securely united together when set in place.

The quartzite which in practice I have found to produce the best results as an ingredient of the composite paving-blocks is found in South Dakota and southwestern Minnesota and also in \Viseonsin but, while I prefer the use of quartzite by reason of its peculiar affinity for hydraulic cement, I do not wish my invention to be understood as restricted to the use of quartzite in thebottom of the block, since other suitable hard stone may be employed as asubstitute therefor, although, as I have stated, the best results will be attained by the use of the quartzite. Nor do I wish my invention to be understood as restricted to the proportions of the ingredients above stated, as these may be varied; and, if desired, the lower portions of the blocks may be formed of a composition different from that of the upper portion oreontainingbroken pieces of stone of larger size than are used for the upper portions of the blocks.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A composite paving block the body whereof is formed of a concrete mass and the lower surface of which is provided with protruding pieces of broken stone securely embedded in the block, whereby the block may be firmly united to the foundation of the pavement, substantially as described.

2. A composite paving block the body whereof is formed of a concrete mass and the top whereof is provided with a dressing of finely-crushed quartzite and hydraulic cement and the bottom whereof is provided with pieces of broken stone firmly embedded therein and projecting therefrom, substantially as described.

JAMES IIAINES DRAKE.

Witnesses:

M. Dwynn, HUGO ScHLnNK. 

